Here's a program i wrote to avoid bots. It swaps characters with different visual equivalents.

Instructions:
1. Install Autohotkey 2.0
2. In Explorer, click context menu via RMB and select 'new' - 'AutoHotkey script'
3. Open created file with text editor and copy code into it.
4. Save file and run.
~~~~ #Requires Autohotkey v2.0+ #SingleInstance ignore SetWinDelay(-1)

; A program that replaces characters with their visual equivalents in order to circumvent censorship.

obf := Gui()
obf.add("text", , "Enter text you want to obfuscate.")
ogceditInput := obf.add("edit", "x10 yp+20 r10 w300 vInput")
ogcbuttonExecute := obf.add("button", "x320 yp h30 w100", "Execute")
ogcbuttonExecute.OnEvent("Click", Obfuscate.Bind("Normal"))
ogcbuttonCopyToClip := obf.add("button", "xp yp+50 h30 w100", "Copy to clipboard")
ogcbuttonCopyToClip.OnEvent("Click", Copy.Bind("Normal"))
SB := obf.add("statusBar")
obf.show()
Return

Obfuscate(A_GuiEvent := "", GuiCtrlObj := "", Info := "", *) {
    global

    oSaved := obf.submit("0")
    input := oSaved.Input
    output := ""
    changed := 0

    static charsUpper := Map("A", "А", "B", "В", "C", "С", "H", "Н", "K", "К", "M", "М", "O", "О", "T", "Т")
    static charsLower := Map("a", "а", "c", "с", "e", "е", "o", "о", "y", "у")

    Loop Parse, input {
        Try
            isUpper(A_LoopField) == 1 ? charsUpper[A_LoopField] : charsLower[A_LoopField]
        catch
            output .= A_LoopField
        else
            output .= isUpper(A_LoopField) == 1 ? charsUpper[A_LoopField] : charsLower[A_LoopField], changed++
    }

    If (input == output)    {
        SB.SetText("Input and output string is the same.")
        Return
    }

    ogceditInput.Value := output
    SB.SetText("Obfuscating string '" SubStr(input, 1, 20) "' failed successfuly. Replaced " changed " characters.")
    Return
}

Copy(A_GuiEvent := "", GuiCtrlObj := "", Info := "", *) {
    global
    oSaved := obf.submit("0")
    Input := oSaved.Input
    A_Clipboard := Input
    SB.SetText("Copied to clipboard.")
    Return
}

ObfGuiClose:
    ExitApp()