Huh?

i think this means that google is performing a search in ha's topics
but i'm pretty courius what this really is too

Yeh I had that idea too. But I thought it a little odd. Perhaps its something built into the IPB software for detecting the Google spider.

Yes, that is the spider.

You can sometimes see Archive.org too.

Google is almost always spidering HA since it gets automatically alerted to new or updated topics.

silly question,
but for example i have a certain 'blog type' of personal page which is incremental in its nature; what that means for google users is that they will land on index.php as seen by google in the past and they will not found the proper content without additional local search..., now what is the usual way to deal with such situations? (well, i could hack index.php and add some meta tags that would say 'noindex, follow' to the index.php itself, but is there a nicer solution?)

smok3: Look into Google Sitemaps: http://www.google.com/webmasters/sitemaps

The gist of it is that you can create an XML file on your website which is like an index of your site. Then you ping Google whenever you update the site (and thus update the sitemap). They download the sitemap, know what's changed, and then spider only the changes. Most blog software has plugin's or other addon software available to create these sitemaps and ping google whenever the content of the blog changes.

Permalinks would certainly help for that too.

there are permalinks, actually some other spider indexes the page properly, otto42; ill take a look.