You want to give value, even in a talk that's only 10-15 minutes long. How do most speakers do this? The cram their talk full of information and spew it at their audience, similar to how a fire hose sprays a home on fire. The sheer force of the water flow destroys what hasn't been touched by fire.
Instead of trying to jam lots of content into your talk, focus on the IMPACT of your talk! Make 1-2 points, support with stories that walk your audience through the experience, and have a way to collect the contact information with those who want more.
Your job is to move your audience emotionally - not just logically! Short talks, webinars, teleseminars, and podcasts can be highly effective in our "on to the next thing" society.
It's easy to pull one or two ideas from your main, 45-minute master talk and prepare into an emotionally-charged short talk that impacts the audience and leaves them drooling for more. Add pauses, voice inflections, and powerful stories that invite your audience to be IN the story with you. Add a compelling call-to-action. Practice the talk out loud at least 10 times. Now you have a "pocket presentation" you'll be able to deliver, with great success when there's little time to prep.