I don't know a way to do it right out of Adobe, but you can use this tool to do what you're asking: http://www.textfixer.com/tools/remove-line-breaks.php. I routinely have to copy and paste pdf material for the web for a non-profit I work for, and I use that tool every time because it works so well. Plus it's free. If you find out how to do it without using a third-party tool let me know!
You are my new hero. This worked like a charm. Thanks!
or you can run this application in the background, you can also exit if you want. It's amazing, I never had any safety issues.
Its an old question but I found another way. in Adobe Acrobat you can go to
File/Save as/ Word or Excel Online
At least it filters out the breaks and you can smoothly copy past. Manual line breaks cannot be filtered out but it saves a lot of time. Especially if you have to copy to html. When you copy the text out it keeps even the ul and li tags so it is ready to go online wihtout extra making bullet point afterwords.
Textfixer is also ok but then you have to make bullet point manually. If you copy text out of a pdf with bulletpoints its not well formated for import into html and you have to make the bulltet points afterwords again. So try first my first descriped method with exporting to Word.
We first lost a lot of time with the Textfixer Method. However, make it better