It was the Bitcointalk forum that inspired us to create Bitcointalksearch.org - Bitcointalk is an excellent site that should be the default page for anybody dealing in cryptocurrency,
since it is a virtual gold-mine of data. However, our experience and user feedback led us create our site;
Bitcointalk's search is slow, and difficult to get the results you need, because you need to log in first to find anything useful - furthermore, there are rate limiters for their search functionality.
The aim of our project is to create a faster website that yields more results and faster without having to create an account and eliminate the need to log in -
your personal data, therefore, will never be in jeopardy since we are not asking for any of your data and you don't need to provide them to use our site with all of its capabilities.
We created this website with the sole purpose of users being able to search quickly and efficiently in the field of cryptocurrency
so they will have access to the latest and most accurate information and thereby assisting the crypto-community at large.
What happens in those few seconds if the coin was double spent? Are you notified before the next block comes in?
I'm not personally notified, no... But if I have a Bitcoin client connected to the network then yes, it (along with all the other connected clients) should be sent every transaction shortly after they happen. It has to-- it might be generating blocks, and the whole point of block generation is to record the valid transactions the client has seen that haven't been included in a previous block.
There's a discussion in this thread of how likely it is that an attacker could "split the network" to successfully double-spend coins.