Prior to reading your post, I had only heard of "Google Alerts". I knew nothing about the service, and frankly, still don't. With that said, I did find some information, which might (or might not) help, if you don't get any other responses.
In an effort to find out what Google Alerts were, I came across "Google Alerts FAQ". It's quite extensive. Additionally, at the bottom of the page, there's an area, where they provide a place to write and ask questions. Something you might want to consider. The article also references "managing your alerts".
I saw your (unanswered) post, from last week, at the Google Community forum. Have you considered posting at another sub-forum, within the community? Some of them seem more active, then where you posted. Just a thought.
I can't help but ask. Is it possible your "web-active" son, who you haven't gotten any alerts about, gained access to your computer/account? And possibly set you up to be "alerted" as to the activities of the tennis pros, Justine Henin and Kim Clijsters? As I said, I couldn't help but ask.
You haven't mentioned whether, or not, you scanned with any software, to rule out "unwanted visitors". If you haven't, I would suggest A-Squared Web Malware Scan. It's an online scanner. If it finds anything, put it in quarantine. If you don't already have Malwarebytes' Anti-Malware installed, I would strongly suggest you scan with that too. Neither will cost you anything, and it's definitely worth a try. If for no other reason, than peace of mind.
Best of luck ..
I use Google Alerts to keep track of the web adventures of my adult
children, and for my own ego. Have setup 3 such Alerts and it's
usually fun to see what they produce, tho only my son ever has any
real reason to be an Alert subject, Lately I've been puzzled by
a byproduct of this system. - Since last December, my Alerts mailbox has included
40 of the following kind of Alerts, together with legitimate ones, 3 for my daughter, 37 for myself, (and none at all for my web-active son):
"justine" || justine henin and kim clijsters rivalry || justine ...
justine roberts justine henin wimbledon 2007 justine humble lbuquerque
justine alessi justine horrens justine brown justine ruckert tasmania ...
The final HTTP domain address has been different in every single one
of these Alerts and links to a page of such entries, with no links
anywhere on the linked-to page, and none of the other domains pages
related in any apparent way to these kinds of entries. There are .com
as well as .org sites. The scripting language is always php.
I'm running this under Windows XP Pro, all updates applied; my main browser is Firefox 3.x with very occasional use of Internet Explorer 7.0
Can anyone tell me what is going on, and whether I have any cause to be concerned? TIA!