Here's something I've never encountered since I converted to Mac religion...
I open Safari, it goes to my homepage and in a couple of seconds it opens another tab (that forces itself to be the main tab) that heads to a variety of advertising, everything from adult stuff to computer stuff...WTF???
So far I've:
Ensured popup blocker is checked/adblock is updated/etc. (the "duh" stuff).
Reset Safari/cleared caches/cookies/etc.
Called the browser various names.
Does anyone have any ideas what is going on with this? I am using the latest/greatest/uptodatest version of Safari.
**In an odd sort of way, I must admit it's somewhat nostalgic as I feel like a frustrated windows/PC user all over again!
What is your homepage? Have you tried setting to different Homepage? What were the results?
Have you tried the same homepage from a freshly created user account?
__________________ ~WARNING: If you see links to ads in the above post, blame the cheesy ad-linking software used by the owners of this website. These ad links were inserted without either my direct or implied permission. I do not endorse these links. Don't click on them.~
Do NOT Touch this computer!!! Touching this computer WILL cause irreversible brain damage.
Check your Tabs preference in Safari and UNcheck the middle option ("make it active") if its checked. That won't solve the mystery of WHY you're getting a new tab, but it will stop the tab from becoming active.
It's could be that those popups are being called by the homepage and not from Safari. If you post the homepage URL, I can check this. You could also try visiting the site in another browser to see what happens.
Sounds like you may have caught a trojan horse. There's one in particular called RSPlug which, among other things, is able to redirect your computer to a rogue DNS server. Though you may not have RSPlug, the behaviour you're describing certainly sounds like a trojan.