Initial coin offering (ICO) is an unregulated means of crowdfunding via use of cryptocurrency, which can be a source of capital for startup companies. In an ICO a percentage of the newly issued cryptocurrency is sold to investors in exchange for legal tender or other cryptocurrencies such as Bitcoin. The term may be analogous with 'token sale' or crowdsale, which refers to a method of selling participation in an economy, giving investors access to the features of a particular project starting at a later date (source: https://en.wikipedia.org/wiki/Initial_coin_offering)
There are plenty of ICO-related sites that people uses to promote ICO:
icocountdown.com
52ico.com
icoinfo.net
icorating.com
icochecker.com/contact
tokenmarket.net
smithandcrown.com
cyber.fund/radar
icotracker.net
icocoins.com
tokeninvestor.com
yunbi.com
icoage.com
allcoin.com
coinschedule.com
icorating.info
icobench.com/publish
cointelegraph.com/ico-calendar
ico-list.com
coingecko.com/ico?locale=en
coinstaker.com
happycoin.club
icocrowd.com/calendar
icobazaar.com/list
cryptocompare.com/ico/
icotimeline.com
cryptocoincharts.info/ico
icowatchlist.com
topicolist.com
applancer.co/ico-list
icocalendar.today
coinmarket.news/kalendar-ico
icostats.com
tokentops.com
foundico.com
icodaily.net
icotoday.io
picoloresearch.com
crushcrypto.com
verifiedicos.com
icodrops.com
tokendata.io
coinfunda.com
They offer free or paid listings (they ask about 0.5 BTC for listing in general, up to 6 BTC!).