text: Junk mails are those which r mostly from online advertising/web marketing sites....\n\nWho sents it and how? Basically they get our Id from some linked sites wherein we have subscribed or smtimes through spywares/spam emails which we open. Mostly they get it from the subscriptions we make when we create an online account in any website/email site. Though mostly used for online marketing...somtimes r used by hackers for malicious activities too....\n\nWhy they go to Bulk folders? Coz bulk folder contains all the mails which are addressed to more than one individual...hence as these mails are meant for online marketing/spamming it contains multiple addresees.\n\nAnd above all Junk is a term what we give to a mail which we found is not useful for us but it may not be junk for somone who is relate to it....\n\nHence it totally depends upon individual perceptions...