So late yesterday the news out of Twilio's Signal conference broke that Twilio was acquiring SendGrid. Most of the coverage is straight out of the news release, with very little critical analysis. From my perspective $2 billion for SendGrid, a company with a perceived market value of $1.4 billion is a nice premium, and a win for their shareholders. For Twilio it adds revenue to the books, and helps with sales and marketing efforts.
Given Twilio has been developer focused until after their IPO while SendGrid is enterprise sales focused, the buy actually helps Twilio become more enterprise oriented, presuming that the SendGrid sales team sticks around, and that Twilio can move more deeply into the enterprise. As someone remarked here at APIdays in Amsterdam, changing direction after you go public (i.e. pivot) isn't something that easily happens. I don't see Twilio pivoting, but instead using SendGrid to blend the SMS/MMS customer more intimately with their email based communications base.
Time will tell.