Make sure you open an external link and PDFs in a new tab/window. It's good website usability.
A great example of website usability. Instead of a blob of text which I didn't read, now contains a few bullets with a clear short sentence.
Website text too small? Here's how to increase the website font or text size on each browser.
When linking, should I open up into a new window or not? Yes when you're linking to a document. No when your linking to a website.