QUOTE (Ternal-sempai @ Jan 9 2011, 12:36 PM)
It depends on how effective you want your SEO to be. iframes wreak havoc on how search engines see your website. They're also horrible for accessibility for the blind, which usually use screen readers, and you can imagine how that works out with iframes.
Any iframe can be replaced with an include() command in PHP (one the most basic commands in PHP), so once you get to that point, iframes are completely useless. That said, for your particular situation I would recommend just linking to the SMF forum on another page instead of trying to embed it. If you do, there are probably ways you can use RSS to your advantage in making the blog appear on the forum.
Kread, the above quote is very similar to what I would have said.
Most programmers will call "blasphemy" when iFrames are suggested due to the fact that they all like to "do things right".
However, their reasoning is based on two things: accessibility and practicality. =]
I'm glad you haven't created a habit of using iFrames, just don't start that habit because it's not worth it. =]