eBay has over 130 million active buyers and more than 1.5 billion live listings. The difference between a listing that sells and one that sits isn't luck — it's optimization. The Cassini search algorithm (eBay's A9 equivalent) ranks listings based on a combination of relevance signals, seller performance, and buyer behavior. Most sellers optimize for none of them.

Here are the five most common listing mistakes that hurt both search visibility and conversion — and exactly what to do about each one.

Titles That Don't Match How Buyers Search

Your title is the single most important SEO element in your eBay listing. Cassini parses it for keywords and uses it to determine which search queries your listing should appear in. Most sellers waste this real estate with filler words, vague descriptors, and brand names that no one actually searches.

eBay gives you 80 characters. The typical buyer search query is 3–6 words. Your title needs to contain the exact phrases — not variations, not synonyms — that real buyers type into the search bar when they're looking for what you're selling.

What Cassini rewards: Titles with high click-through rates, conversion rates, and keyword relevance. Titles with vague terms have low CTR — and Cassini buries them further as a result, creating a downward spiral.

The "before" title contains zero searchable specifics. No brand, no model, no specs. A buyer searching for "Canon Rebel T7" will never see it. The "after" title hits brand, model, product type, spec, and condition — all the fields buyers actually search.

Fix Use the format: Brand + Model/Type + Key Spec + Condition. Include the most specific searchable terms first. Drop adjectives like "nice," "great," "amazing" — they're invisible to search and waste character space. Use eBay's autocomplete to validate your keyword choices before publishing.

Descriptions That Don't Sell

eBay descriptions are where most sellers either phone it in or actively drive buyers away. Two failure modes dominate: the wall-of-text dump and the three-line non-description. Both cost you sales — just differently.

The wall-of-text dump tries to include every detail but makes it impossible to scan. The buyer needed to confirm one specific detail (is this compatible with my model?), couldn't find it in 10 seconds, and left. The three-line non-description says "item as described in title, see photos." That's not a description — it's an invitation for buyers to assume the worst about anything your photos don't show.

Your description does two things: it reinforces search keywords (Cassini indexes it) and it closes the sale for buyers who are almost convinced but need one more nudge or one more confirmed detail.

The "after" description answers every question a serious buyer would ask before clicking Buy It Now: what's included, condition details, shutter count, what accessories come with it, and how it ships. Buyers who read this have almost no reason to hesitate.

Fix Write your description using this structure: product overview → condition details (including any flaws, explicitly) → what's included → shipping info. Answer the questions a buyer would ask before messaging you. If you're getting a lot of pre-sale questions, your description is missing something — add the answer.

Ignoring eBay's Item Specifics

Item Specifics are the structured data fields eBay provides for each category — Brand, Model, MPN, Color, Size, Condition, Compatible With, and dozens of category-specific fields. Most sellers either skip them entirely or fill in only the required ones.

This is one of the most overlooked ranking factors in eBay SEO. Cassini uses Item Specifics to match listings to filtered searches. When a buyer searches "men's Nike running shoes size 11" and filters by brand, size, and color, only listings with those Item Specifics filled in correctly will appear in filtered results. If yours are blank, you don't exist to that buyer — even if your title says "Nike running shoes."

eBay's own data shows that listings with complete Item Specifics rank significantly higher in Best Match and appear in more filtered search results. Completing them takes 3 minutes and can permanently improve your listing's visibility.

Beyond search, Item Specifics also populate eBay's product pages and comparison tools. Buyers using eBay's catalog-based browsing rely on these fields to evaluate options side by side. Blank specifics mean you're invisible in those pathways entirely.

Fix Go into every active listing and complete all available Item Specifics — not just the required ones. For electronics: include MPN, compatible models, storage capacity, color. For clothing: size, material, style, occasion. For collectibles: year, manufacturer, country of origin. Use eBay's suggested values where available — they're drawn from actual buyer search behavior.

Keyword Stuffing (Or No Keywords at All)

Two opposite extremes both hurt. Sellers who've read outdated SEO advice try to cram every possible keyword into their titles and descriptions: "Canon Nikon Sony Camera DSLR Digital Camera Photography Equipment Professional Camera." This is keyword stuffing, and Cassini penalizes it. Listings like this also have terrible click-through rates because they read as spam to real buyers.

On the other end, sellers who don't think about keywords at all use natural language that describes their product accurately but doesn't match how buyers search. "Wireless headphones with good bass and long battery life" — accurate, but buyers are searching "Sony WH-1000XM5 wireless headphones noise canceling." Natural language ≠ search language.

The keyword-stuffed version triggers spam filters and gets buried. The optimized version uses the exact model name buyers search, adds the most important feature phrase (noise canceling), and includes the most commonly filtered attribute (condition). It reads like a human wrote it and ranks like an SEO did.

Fix Find keywords by typing your product into eBay search and recording autocomplete suggestions — these come directly from real buyer behavior. Use 1–2 primary keyword phrases in your title (brand + model + category). Add secondary keywords naturally in your description: "compatible with," "works with," "ideal for." Never repeat the same keyword more than twice.

Listings That Break on Mobile

More than 60% of eBay traffic comes from mobile devices. If your listing description uses HTML tables, large fonts, center-aligned layouts, or custom CSS that was designed for desktop, it either renders poorly or doesn't render at all on phones. Buyers who can't read your description don't buy — they scroll past.

This is most common in listings that were created with eBay's old HTML editor or imported from third-party listing tools that output complex formatting. The result: on desktop, your description looks polished. On a phone, it's a broken table with microscopic text or a horizontal scroll nightmare.

eBay now actively demotes listings in mobile search results if the description contains HTML that doesn't render cleanly on mobile — particularly JavaScript, complex CSS, and fixed-width tables. This is a ranking issue, not just a UX issue.

The safest description format is plain text or simple HTML: paragraphs, line breaks, and basic bullet points. No tables, no custom fonts, no JavaScript. If you want visual structure, use eBay's built-in listing editor which generates mobile-safe markup automatically.

Fix View every active listing on your phone. If the description is hard to read, rewrite it in plain text with simple formatting: short paragraphs, bullet points with line breaks, no tables. Use eBay's native listing editor instead of third-party HTML. After updating, check the listing on both iOS Safari and Android Chrome to confirm it renders cleanly.

How These Mistakes Compound

Each of these mistakes costs you separately — but they compound against each other. A listing with a weak title doesn't get found, so it gets low impressions. Low impressions mean low total clicks. Low clicks mean eBay's algorithm has little data to work with. With little data, Cassini defaults to conservative ranking, which means fewer impressions. The listing stagnates.

Fix the title, and impressions increase. Fix the description, and conversion rate improves. Fix Item Specifics, and filtered search visibility expands. Fix keyword strategy, and you capture long-tail buyers you weren't reaching. Fix mobile, and you stop losing the 60%+ of traffic that's on a phone.

The compounding works in both directions. Sellers who fix all five see dramatic improvements — not because each fix is magic, but because the fixes reinforce each other. Better impressions plus better conversion plus wider search coverage equals significantly more sales from the same product.

Start with your top 10 listings by traffic. Run them through each of these five checks. The ones that fail multiple checks are the highest-leverage targets — fix those first.

The Fastest Way to Fix All Five

Auditing and rewriting listings manually takes time — especially if you're running a store with dozens or hundreds of SKUs. The most common outcome is sellers fix one or two listings, get distracted, and leave the rest underperforming.

Aislo's optimizer handles the heavy lifting: paste in your product details, select eBay as your platform, and it rewrites your title, description, and keyword strategy — optimized for Cassini, written for mobile, structured to convert. You review the output, make any tweaks, and publish. Three free optimizations to get started, no credit card required.

Conclusion

eBay rewards sellers who make it easy for both the algorithm and the buyer. Cassini needs clean keyword signals to know when to show your listing. Buyers need complete, scannable information to trust that what they're buying is exactly what they expect.

Most sellers are unknowingly failing on both fronts — not from lack of effort, but from not knowing what Cassini actually weights and what buyers actually need before they'll commit to a purchase.

The five mistakes above — weak titles, thin descriptions, empty Item Specifics, poor keyword strategy, and broken mobile layouts — are fixable in an afternoon. The sellers who fix them don't just sell more; they build the seller performance metrics (click-through rate, conversion rate, low returns) that compound into better rankings over time.

That's the eBay flywheel. Better listings generate better performance data. Better performance data earns better placement. Better placement brings more buyers. It starts with the listing.