My Friends whose petitions got filed after may 16th have received petition numbers already. Will USCIS process the petitions randomly or sequentially ? will they not process the petitions in order ?
I presume they process the petitions sequentially on a weekly basis (week-by-week).
USCIS had a [press release](http://www.uscis.gov/portal/site/uscis/menuitem.5af9bb95919f35e66f614176543f6d1a/?vgnextoid=48c78976a0a77310VgnVCM100000082ca60aRCRD&vgnextchannel=e7801c2c9be44210VgnVCM100000082ca60aRCRD) in May which suggests that there could be a delay in sending out the receipt notices to the peitioners and you should expect your receipt notice to be send out by mid-July.