posted on Sep, 7 2010 @ 06:46 AM
When you visit the site, they capture details about where you are, who you are, what computer you're using, and so on. This is logged to a database.
Then the site owner can look up the details of who is visiting their website, which pages are being visited, products purchased, they can also track
the page you entered from and the page you left to. That lets companies track the effectiveness of marketing campaigns, so if you get an email saying
here's 20% off the new version and you follow the link to make a purchase they can see if you're worthwhile targeting for future campaigns and so
on.
There is a very genuine and useful side to GA, there are plenty of readable books out there on how to do it for your website. I expect there is a
nefarious side too, but that's for others to explain.
Any slowness probably comes down to slowness of their database servers in recording the details to a database, or other issue with their server
farms.
How paranoid you want to get over this is up to you, for my money I wouldn't worry too much about it. What could you do anyway?