I often see people (not specifically on [RaspberryPi.SE]) use sites like
pastebin.com to post logs.
Stack Exchange has no control over these sites and these sites are free to place any ads on their site as they please. They are also free to remove the content whenever they please.
So, personally, I prefer to always include the log in the question (as long as it is possible due to the length). Code blocks get scrollbars when they need them. So, visually, it's not too bad.
What's your opinion on it?
This question came to mind due to this question: How do I install Jenkins?