I don't often write about individual smartphone apps, but this one catches my attention because 1. It's rather good and 2. it shows Apple how proper email search should be done.
'reMail 2' (#1 passed us by) is a remarkably fast and comprehensive alternative to the iPhone's own default mail client. Much like the existing client, it can download new email, reply or forward it and write and send new emails. What is its key differentiator however is lightning fast, full text search.
In essence, this means searches can be made for senders, subjects or through any body copy and results are returned virtually instantly with your search terms clearly highlighted. How does it manage to be so comprehensive and eliminate any semblance of lag? Because, unlike the iPhone email client, reMail 2 downloads the full content of your inbox.
This might sound like a storage nightmare but attachments are left out, unless requested, and everything is heavily compressed. For example, the 45,000+ emails in my account were downloaded overnight and took up just 300MB of space instead of the near 5GB they occupy on my mail server. The second benefit is you don't need to be online to search your entire email contents. Handy when either without signal or when travelling abroad to avoid data charges.
The downside to reMail 2, for my money, is it's overpriced at £2.99. It also doesn't support Exchange and you can only sync one account at a time. That said, if you regularly need to search for information in your email then it is worth its weight in gold and certainly shows Apple how to do email search properly...
17.02.10 Update: Google has now bought reMail for an undisclosed amount. Clearly it has an eye for talent and its eventual integration into Android could be quite something. Consequently reMail has been removed from the App Store, but existing users can keep using the app. The code for the reMail iPhone app has also been made open source.