Users who are using reMail on iPhone may have to find a similar app to fill in reMail’s place! Google has purchased reMail and had removed this app from iPhone store. reMail is convenient because it’s fast and you don’t have to be connected to the Internet to search for a specific email.
How reMail works? It downloads all of your emails and store those on your iPhone. reMail’s search speed is very fast and so even if you have thousands of emails store on your iPhone, using reMail you could still find an email within 2 seconds. Doing all of that without being connected to the Internet since reMail has downloaded all of your emails onto your iPhone when you were connecting to the Internet previously.
We all know that Google has Nexus One and Android for other smart phones. From the purchase of reMail, it could mean Google is planning to release reMail or marrying reMail with Google’s compatible products. Android users may see something similar to reMail, but iPhone users may have to go without reMail in the future. Source.