It's perfectly acceptable to ask in a thread where you see an acronym. Techies tend to use more than their fair share of acronyms and other jargon, and they are not always forthcoming about what they mean, assuming that if they know them, everyone does.
If you are too shy to ask in a thread, or it looks like something that you should know based on the context of its use, you can always visit The Acronym Finder. They've got all the biggies, including DSLR and BBR.
The shortcut speech used in IM's, posts, and chat rooms changes almost daily, but some are with us forever. This link explains the most common ones, as well as some of the often-used emoticons: WebSlang.
It's an emoticon, an ASCII glyph. A fairly complete list is here: Emoticons. The standard set of Broadbandreports.com graphical smilies is here, although you are not limited to those, and can link to thousands found all over the web.
Now, it's mostly a nostalgic piece of history dating from the days of Bitnet and Listserv. But there was a time when you were nobody if you didn't have one of your own...a time when people were proud of their geekiness!
An example:
-----BEGIN GEEK CODE BLOCK----- Version: 3.1 GE/M/S/TW d@? s:(-) !a C(++++) UHC*(+++)@ P+ L E W>-- N(+) o K-- w(+++) O M V PS@ PE@ Y(++) PGP(++++) t 5 X R tv? b$ DI D G(+++) e(+++++) h(++)@>++ r$ z*$ ------END GEEK CODE BLOCK------
In the days of slow access, you could tell someone a whole lot about yourself in a very concise way, by including your personal Geek Code as a signature.
Real geeks memorized every code, and could read them like regular text.