It may be a pun, composed of a portmanteau of the words "Summer" and "Summary". This hypothesis would seem likely because:

1- I believe it's the first time this orthographic mistake was made from this account.
2- Summer began yesterday.

It may be a bit subtle, but in my opinion that only adds to the pun quality.
If it is indeed a pun, I deem it significantly witty and fun, rating it 7.4/10.