It's true. Here at Marketo we use Slack, and our Slackbot HATES server side post.. so much so that when you mention it, it chastises you. It's really pretty amusing.
![Slackbot.png Slackbot.png](/t5/image/serverpage/image-id/17631iE54A551A41652CB3/image-size/large?v=v2&px=999)
Fine! Jeez.
Really though, Slackbot is completely right. Server side post has effectively been replaced by the following REST endpoint, which is great and scalable.
http://developers.marketo.com/rest-api/lead-database/leads/#push_lead_to_marketo
This, along with my other most recent blog, provide a good blueprint for associating leads in a non marketo form with only one REST call. No fewer than 3 customers have had this very question for me this week alone, so it seems like a hot topic.