A Swarm of Bots Is Taking Over Crypto Telegram
It’s important for ICOs to have a respectable Telegram following. It’s a ready reckoner that enables prospective investors to gauge, at a glance, the level of interest in the project. Twitter followers can easily be bought, but Telegram numbers, so the consensus goes, are harder to fake. Harder, but by no means impossible, and because Telegram is more of a closed network than Twitter, it’s harder to scrutinize the quality and “humanity” of a group’s followers. And with news breaking that up to 70 million Telegram account usernames and phone numbers have been leaked and are for sale, bot-based scams are likely to proliferate.
It’s common for ICO Telegram groups to be inundated with followers after launching an airdrop because this is a requisite to claim the free tokens. After kickstarting its airdrop last week, for example, Kleros, a blockchain dispute resolution layer, saw its Telegram followers mushroom from 500 to over 6,000 in 48 hours. The project’s community manager, Stuart James, told news.Bitcoin.com that Kleros welcomes the influx but is keen to ensure that airdropped tokens are distributed to “genuine” community members only, explaining:
After a while you get a feel for the sort of behaviors that have the hallmarks of bot activity. Shortly after joining a Telegram group, they’ll post similar replies to the pinned post, and engage in other programmatic responses. Evidence suggests that the majority of our new Telegram followers are human, but there’s a subset that is clearly bot-based, and it’s the same in the other ICO Telegram groups I’ve spoken to.
Not All Bots Are Bad
There is nothing intrinsically good or bad about bots: it’s how they’re purposed by their operators that defines them. ICO groups use their own bots, for example, to perform automated checks of whitelist signups and to issue generic greetings and crowdsale information to new arrivals. Biondi, a Telegram bot dev with the handle 
I would speculate that [airdrop bot operators] have a pool of phone numbers (probably thousands) where they register an account, PM the airdrop bot and join the chat. But those are non-malicious (maybe just a waste of server resources). The more worrying ones will be scammers who impersonate admins and PM users for ETH, promising them tokens, often with a bonus. Those work by getting the chat participant list and privately messaging all of them. A human then handles the response and interaction where ETH is often requested.