Sure you are...

vbseo is no more, the company website is shut down as well.

Wrong, the site is now back up.

Only partly correct - while the website is up for sales of vbseo (yes, they want your money), the support section of the site is dead. This is because vbseo is already dead; it just forgot to lie down.
http://admin-talk.com/threads/dear-v...rations.43684/

There will be no further versions of vbseo (none for vbulletin 5, for example); there will be no further support from vbseo.

Source? :rolleyes:

From vbseo 7/30/2013: "Hello,

Unfortunately we will not offer compatibility with vBulletin 5.

Kind regards,
Andr?s Dur?n / Crawlability Inc.
vBSEO Sales Specialist."

vbseo no longer responds to support tickets. Open one and see if you ever get a response.

As well, the sibling founders of vbseo have been feuding for some time and the sister states, as noted in the above link, that vbseo will be closing down soon.

So what is the best replacement SEO software for vBulletin forums if/when VBSEO shuts down for good?

You don't need vbseo in the first place, so I don't see the need for a replacement ;)

Proper use of keywords and thread titles is all you need. I get hit by google and other search engines like crazy and I am not having problems with SEO on my site at all.

If you have fresh content and manage to figure out how to get your forum's members involved in the discussions you don't need anything like vbseo.

You'll also get smart aleck snark and attitude from "support" here, just so you know. But thanks for sharing. I hope your paypal dispute works out.....