How Unique is Unique?

[basha]

We're trying to populate our website with lots of content. We'd like to reuse some where possible on other sites but don;t want to get a duplicate content penalty.

How unique does the content have to be on the other sites? Can we just change one word per sentence?

[owl]

Basha, there are software programs that could be used to estimate the degree of unique-ness, and copyspace is one of these.