A userscript which allows uploading .blends to Blend-Exchange directly from the editor on blender.stackexchange.com.
This script should work with just about any userscript manager, but it has been tested with greasemonkey and tampermonkey.
Once you have a userscript manager installed, you can install the script via OpenUserJS, or just install it directly by clicking here.
Click the icon above your post editor or press or press CtrlB to upload a .blend.
Note that the script is disabled when writing as yet unposted questions. This is because blend-exchange requires the question url to verify that what is uploaded is actually a legitimate .blend used on blender.stackexchange. Since obviously the question url is unknown until you've posted your question, in order to upload your .blend on a question, you'll have to first post the question, then edit it and upload then.