Screenshots of a service called Google Base started circulating after bloggers who closely track the company discovered that the domain base.google.com temporarily resolved to a landing page for the pre-launch service.

The service was partially live again at time of writing, but had quite a lot of dead links and didn’t appear to fully function.

Google Base is Google’s database into which you can add all types of content. We’ll host your content and make it searchable online for free, the landing page reads. You can describe any item you post with attributes, which will help people find it when they search Google Base.

This means, as bloggers and several media outlets postulated, that Google is getting into the classified advertising business, and eBay is in for some rough competition.

The latest chapter in the often-fantastic saga of Google is now out. This time, it’s about how Google plans to crush eBay, one report began, before noting, the Google Base web page makes no mention of an auction or online sales capability.

Just days before the partial launch, when Base was still in rumor form, eBay’s market capitalization lost about $2bn. The company got lucky – Microsoft lost $5.6bn of market cap due to speculation about a non-existent Google service earlier in October.

Some bloggers took the hypothesizing further, speculating on the impact of Google Base on database software, although to our knowledge nobody in the blogosphere is predicting the death of Oracle et al just yet.

Is Google putting a layer in-between dynamic web sites and their databases, replacing MySQL/PostgreSQL/MS SQL, and creating a new GoogleSQL… possibly, with their ads in it? one widely quoted blogger wondered.

While Base will certainly get Google into the classified ads business, the scant available evidence seems to suggest that Google is mainly trying to improve its ability to index and provide access to structured content.

Google product marketing manager Tom Oliveri, blogged thus: We are testing a new way for content owners to submit their content to Google, which we hope will complement existing methods such as our web crawl and Google Sitemaps.

Sitemaps enables webmasters to improve their coverage in Google’s main index by submitting a URL map of their site. It essentially creates a structured metadata layer on top of the unstructured content of their web site.

Google Base in its current form appears to allow users to submit data about diverse subjects according to predefined record types, like recipes or housing, or under new record types they create themselves.

Records have a URL field, so there’s obviously an opportunity for web site owners to replicate their existing content in Base, but wrapped in the additional metadata that a database allows, possibly increasing the relevance of their hits.

Google gave as examples of possible record types: Description of your party planning service; Articles on current events from your website; Listing of your used car for sale; Database of protein structures.

Google certainly plans to let users post classified ads, and will allow merchants to upload large numbers of product records in batch files, there’s no indication yet that the company will offer an e-commerce capability at launch.

The company is known to be internally testing a service called Google Purchase, but so far the limited evidence suggests that the service will be at first focused on users buying things from Google, not from each other.

It seems doubtful that eBay, which makes a lot of money managing auctions and processing e-commerce transactions, will be crushed any time soon. While Google Base certainly looks intriguing, its success is by no means assured.

Google has a spotty history with new product launches. For every novel take on a proven concept, such as Gmail and Google Maps, there has been a mediocre me-too, such as Google Talk or Google Groups.

Because Google Base will rely heavily on user-submitted content to be of value, the most similar service may be Google Groups, which has been notably unsuccessful and still relies mainly on Usenet for its content.

It’s also going to be an instant target for spammers, which have already managed to pollute Google’s regular index, as well as populate Blogger with splogs. It’s probably only a matter of time before people are talking about basepam or somesuch.