About
“Hey its me ur brother” is a line from an attempted scam of a user’s expensive in-game item. The phrase is now most often used in jest to express lighthearted jealousy for another person’s belongings.
Origin
A screenshot of a Steam message conversation was posted to the subreddit /r/GlobalOffensive by user /u/EvilClone128 (account since deleted) on June 21st, 2014 [1]. It became one of the highest rated posts on the subreddit at the time.

Since then the image has gained nearly 2,000,000 views on imgur as of November 2015 [2].
Spread
The phrase has since circulated throughout reddit, frequently appearing in the comments of many posts. Few examples exist in 2014, as it has become increasingly more popular since the second quarter of 2015.
Search Interest
External References
[1]Reddit – Best scam attempt I’ve ever seen / Posted on 6-21-2014
[2]imgur- Best scam attempt I’ve ever seen / Posted on 6-21-2014