Academia vs Business
by Jeff
Image text: Some engineer out there has solved P=NP and it's locked up in an electric eggbeater calibration routine. For every 0x5f375a86 we learn about, there are thousands we never see.
This comic is a flow chart defining what would happen if this person solved an impossible problem given to him and what would happen if he were in academia or in business. The argument seems to be here that Academia is much better than business, at least for the ego.
p=NP problem is one of the great unsolved problems in computer science. The Clay Mathematics Institute has a $1 million prize to the first person or group who solves it.
EDIT: As mentioned by just about everybody in the comments, 0x5f375a86 is the algorithm to approximate the solution to the square root of an unsigned floating number, also known as fast inverse square root. The solution uses an ingenious first approximation and the difficult problem was solved without any fanfare (like in the cartoon) for the game, Quake III Arena. Thanks everyone!
Branding
by Jeff
Image meta text: Actually, 'RSS&M' is kinda catchy.
This comic is in reference to a Firefox extension called 'Adblock', which exactly as the name implies, blocks ads on websites. So, without Adblock, you will see all the ridiculous ads (except for our ads, they are great!) that attempt to get you to click on them with their catchy slogans.
The first two frames are not far off from reality, in fact I may have seen them before. Facebook and Twitter are widly known social networks. Google Reader is an RSS reader built on the google look and feel. The meta text references putting RSS and S&M together for RSS&M.
In the last frame, github is an online collaboration tool for developers to upload code to work with other developers on their projects. So, presumably, the comic is speculating that there will be a new GitHub, this one for only lesbians. This is the pop-up windows attempt to attract clicks and in the comics case, it might have worked.
This xkcd is one of the rare xkcd's to use color.