Limerick
Limerick
[Cueball sits at a computer, typing.] Cueball (typing): I used to find slashdot delightful, Cueball (typing): but my feelings of late are more spiteful; Cueball (typing): my comments sarcastic Cueball (typing): the iconoclastic Cueball (typing): keep modding to plus five (Insightful).

A limerick is a well-known type of poem that is usually humorous or bawdy. Technically, a limerick is primarily anapestic trimeter : each line contains three "feet," each foot consisting of two unstressed syllables followed by a stressed syllable. The rhyme scheme is AABBA: the first, second, and fifth lines rhyme, as do the shorter third and fourth lines. Almost anyone can instantly recognize a limerick after hearing the first line.
Slashdot is a venerable techie site. On many sites, the user base can vote comments "up" or "down," but at Slashdot, only moderators (these are randomly drawn from the pool of registered users) may up or down vote comments, and the moderator may select a reason for their up or down vote. Instead of a simple +1, a comment may be voted +1 (Funny). Similarly, instead of -1, a comment may be voted -1 (Off-topic). +5 is the maximum positive score. A comment rated +5 (Insightful) has been upvoted at least 5 times, and has a plurality of "Insightful" votes.
Cueball 's limerick says that he does not like Slashdot anymore, because his sarcastic comments are being treated as "insightful" by the very people he's being sarcastic to.
The title text refers to the notoriously awful comments on YouTube, many of which are so idiotic that they're interpreted as jokes.
In both cases, Randall is invoking Poe's Law . Both sites have become so full of extremes that you can no longer mock the extremists without looking like a sincere extremist yourself.
301, the number of this comic, is also a number often associated with YouTube. At the time this comic was published, view counts on YouTube videos would often freeze at 301, as YouTube would switch between view-counting algorithms when the number of views exceeded 300. Therefore, the comic number itself may be a reference to the title text.
[Cueball sits at a computer, typing.] Cueball (typing): I used to find slashdot delightful, Cueball (typing): but my feelings of late are more spiteful; Cueball (typing): my comments sarcastic Cueball (typing): the iconoclastic Cueball (typing): keep modding to plus five (Insightful).
