People can see me when I should be invisible! What do I do?

Frequently, while playing as a hero that relies on invisibility (such as Broodmother), there comes a point in the game where I should be invisible, yet people walk right up to me and attack me anyway.

How do they do this and how can I counter it?

Solution 1:

Several items or skills in the game reveal invisible units. Here is a list and few tips on how to counter the problem :

Items

• Dust of Appearance : purge yourself Eul's Scepter. Manta Style also dispels dust.
• Sentry Ward : get a Gem or your own sentries to deward.
• Gem of True Sight : gank the carrier.
• Necronomicon (level 3) : kill the Necronomicon units but keep in mind that the ability "Last will" from Necronomicon units level 3 will deal 800 magical damage to the killer.

Skills

• Thirst (Bloodseeker) : not much you can do except run.
• Amplify damage (Slardar) : you can purge yourself with Eul's or use Manta Style.
• Track (Bounty Hunter) : you can purge yourself with Eul's or use Manta Style.
• Lightning bolt and Thundergod's Wrath (Zeus) : not much you can do except run.

Extra Information

Always be aware that the enemy team will sooner or later get a way to detect you. By checking regularly the enemy's heroes inventories and looking for detection items, you can avoid a lot of unfortunate deaths.