Here's another interesting online application that I think is very useful... an online dictionary that makes checking extremely easy, especially when there are lots of technical or unfamiliar terms.
What we need to do is to submit the URL to the site. The application would 'overlay' the 'dictionary' on the text such that one can simply click at the word to display the explanation. Of course, one needs to decipher which is the most relevant/ appropriate explanation, accordingly to the context.
Here's a sample: