Flash Site Optimisation - Popups or not to Popup?

Should my full Flash site use a popup window? Or should the splash/detection page open the Flash in the same window?

I ask this because intitial peer review of my site as lead people to ask for it not to generate a second popup.

I don’t fully understand the advatages of using a popup other than it generates another page which can be useful for extra search engine meta data - and prevents inexperienced users navigating away from the site too easily with the Back button.

What are the advantages/disadvantages of a popup for a full flash site - and how do I make a non-popup version which works well?

Regards,

magic_dot