I always find people on steemit go to posts of others and ask them for follows and upvotes. This won't work here because their follows are meaningless if they don't care about you, and the number of each person daily upvotes are limited so they have to choose who to vote for carefully.

source: pixabay
Why The Number Of Upvotes Is Limited
Each %100 upvote removes %2 of your Voting Power, so if you vote at %100 your next %100 vote will be as if it were %98 and the next %96.. your Vote Power decreases each time. and it regains %20 daily at most... so most people won't Upvote once they reach %70-80 of their Voting Power.
When you have enough SP to unlock Voting Power slider (or if you use chainbb.com instead of steemit.com). The %XX vote gives the post you voted for %XX of the amount of the %100 vote and decreases your voting power by the same percentage.
So people can make about 10 Upvotes only at %100 or 100 Upvotes at %10 daily while staying efficient, maybe more but not by a lot. so they have to choose who they vote for!!
The Power Of Vote, How Many SBD Each Vote Give
Your vote value depends on the amount of SP (Steem Power) you have, according to what I saw someone with 100 SP will have around $0.01 value (while STEEM value is around $1). You can check your vote value in many sites like Steemnow.com, & Steemdollar.com (which tell you the SBD the person you voted for will get rather than the combined value)

meme - source: internet
Why Can't You Vote Exchange Here?
As you see above.. with limited number of upvotes a person can give, and with the different upvote power of each person. It's a huge mistake to expect someone to upvote you back on steemit....
If their upvote power is bigger than yours, then it's a losing deal for them...
If their upvote power is smaller than yours, then it's a losing deal for you...
The only two cases I know where the upvote back is fair:
- One: is when both users vote with the same SP and the same voting power percentage.
- The second: is when the one who asked for the upvote offers something with value. that's why I don't mind people who ask for upvotes in their own posts that are obviously made with a lot of work/care.
But in the case I've seen a lot of newbies make lately, it's not like that at all... the way they ask for upvotes are like someone who gives you $1 and tells you, hey!! give me my $10 back!!

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Conclusion
With how the systems works, there are rarely two people who have the same voting power at the same time... and a newbie will likely have zero until they post a big amount of posts and/or comments. so telling someone to upvote you because you upvoted them isn't likely to give you a good response. Especially from whales who got used to spammers doing that to them.
I hope this post make some people realize, how bad these comments are for the community...
And I hope this makes more people post a comments that add value instead of "Thanks for sharing" comments. I wrote an article about this few months ago... but I'll probably rewrite it and post it again with more info. so stay tuned.