What's the best common format for an eBook like text to share with most of the mobile phone types

There is a description about a product or event that people would like to share among them. This can be a simple text or rich text too.

They are looking into which format is the best for this purpose. They would like to see compatible with as many phones as possible. We are talking about phones that have Bluetooth.

Also the text is longer than the length of an SMS, so the SMS format is not s开发者_JAVA技巧uitable

What would you recommend?

And what do you think what would be the best way to share that between phones?

The most simple format would be preferable, so my view is a simple text format using Unicode. My guess is that every handheld device is able to read the simple text format. No style, no color, no font weight, no ... is attached to the simple text format. Boring? Yes! Yet useful.