How many tags per post will Traffic Goliath return?

When you search for a tag, Traffic Goliath will search for tags on sites like on Google, Youtube, Amazon, Bing and Wikipedia

Once the tags are fetched, the plugin will add them all together and deduplicate the list of tags.

The number of tags will depend on the keyword you use, as well as on whether you use the basic or the PRO version of the plugin.

Another answer can be "as many tags as the big sites return". :-)